feat: Implement time travel (snapshot rollback) capability

[sayansil]

This commit introduces a feature allowing you to revert the simulation to a previously saved state from a specific year.

Key changes include:

• Database & State Management:

  • DatabaseManager can now save and retrieve the complete raw simulation world state (RAW_WORLD BLOB) for each year, in addition to summaries. This required a manual schema change to add the RAW_WORLD column to ECOSYSTEM_MASTER.
  • Methods read_row_by_year and get_available_years were added to DatabaseManager for targeted snapshot access.
  • The God class's load_snapshot method now restores the full simulation state from the raw world buffer, ensuring accurate rollback.
  • God::happy_new_year now saves this complete state when gods_eye is enabled.

• Python API:

  • The pyecosystem Python wrapper now exposes: - load_snapshot_from_year(year): To load a snapshot. - get_list_of_available_snapshots(): To list savailable years. - get_current_year(): To get the current simulation year.

• Example & Documentation:

  • A new Python script Python/sample_timetravel.py demonstrates how to use the snapshot feature.
  • docs/README.md has been updated to briefly describe the new feature and the manual database change required.

This feature allows for more flexible exploration of simulation dynamics by enabling you to revisit past states and explore alternative evolutionary paths.

Description and Context

Best Practices

• My code follows the code style of this project.
• The code base is in a better state after this PR.
• The level of testing this PR includes is appropriate.
• I have considered the impact that this change will cause on application performance.

Git requirements

• I don't have multiple unrelated changes in the same PR.
• My branch is in sync with latest production branch.

[sayansil]

@hit-11 someone has picked up your feature-request 😌